A pullulanase is an enzyme which can degrade alpha-(1,6)-linkage of pullulan, amylopectin and other branched substrates. In the grain industry, bacterial pullulanases have been used for the purpose of removing alpha-1,6 bonds in starch, which may cause undesirable panose formation in the saccharification process.
Two different classes of pullulanases are known: EC 3.2.1.41 which include two types (type I and II) of pullulanases and EC 3.2.1.135 referred to as “neopullulanases”.
WO 95/23852 discloses an amylopullulanase from Thermococcus celer and the use for producing 5 sweeteners and ethanol from starch.
A pullulanase type II (family GH57) from the hyperthermophile Thermococcus hydrothermalis is disclosed as UNIPROT: Q9Y8I8.
A pullulanase type II (family GH57) from Thermococcus litoralis is disclosed in UNIPROT: Q8NKS8.
WO 98/26058 concerns a pullulanase from Thermococcus hydrothermalis CNCM 1 having a temperature optimum of 110° C. at pH 5.5 and the use thereof in combination with an alpha-amylase and alpha-glucosidase for producing syrups.
The object of the present invention is to provide pullulanases expressed in increased yields and/or having higher thermostability, respectively, compared to a parent pullulanase in question.